1. Field of the Invention
The present invention generally relates to a vehicle cowl box structure. More specifically, the present invention relates to regulating air flow through a vehicle cowl box structure to a vehicle HVAC system.
2. Background Information
For many years, automotive vehicles have been provided with climate control systems (e.g., heating, ventilating and air conditioning (HVAC) systems) in order to provide a more comfortable environment for the driver and any passengers. Typically, fresh air is supplied to the HVAC system via ducts extending from a cowl box structure of the vehicle. Generally, the cowl box structure is a structure that is disposed in an area between a front windshield and a fire wall of an engine room. The cowl box structure usually has an upward opening with air inlets that have louvers. The air inlets of the cowl louver are provided so that outside air is drawn into the cowl box structure. The air drawn into the cowl box structure is then used for the air conditioning and/or directly sent to the vehicle interior through a duct coupling the cowl box structure and the vehicle interior.
At higher vehicle speeds, a “ram air effect” occurs on the air inlet of the cowl box structure due to the increasing airflow volume being forced into the cowl box structure at increasing vehicle speeds. In vehicle HVAC systems that have automatic variable blower control (VBC), the “ram air effect” can be compensated for by modulating blower speed directly. However, in lower cost HVAC systems without automatic variable blower control (VBC), the “ram air effect” that occurs on the air inlet of the cowl box structure can cause an undesirable air rush noise in the cabin of the vehicle.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved vehicle cowl box. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.